1. Field of the Invention
The present invention relates to an earphone jack and a mobile terminal, and more particularly, to an earphone jack and a mobile terminal having the same so as to enable a plug to be smoothly inserted into or pulled out of an earphone jack regardless of diameter variations of the plug and the earphone jack without providing an additional part.
2. Description of the Background Art
A mobile terminal is a communication device which permits the voice transmission and reception with an other party anywhere while a user portably carries it along. With the development of information and communication technologies, such a mobile terminal has not only a function of sending/receiving voice messages to/from the other party but also a function of sending/receiving image information.
Also, the mobile terminal is continuously being developed so as to have improved performance and exterior and various functions in response to the growing demand of consumers. Of the various functions, an earphone supporting function is being considered as an essential function of the mobile terminal. This is because as mobile terminals are commonly used due to developments of a wireless communication technology, the quality of communication is more importantly considered. In order for the high quality communication, an ear-microphone provided with both an earphone and a microphone is commonly used, so that a user may conveniently make a call by inserting (connecting) the ear-microphone into an earphone jack of the mobile terminal while driving or walking. Also, since an MP3 function of replaying downloaded music is additionally provided to a recently released mobile terminal, its user may listen to the music by connecting a headphone or a headset to the terminal.
In this specification, an earphone, an ear-microphone, a headphone, a headset, and the like will be collectively referred to as an earphone.
In general, a mobile terminal, a PDA, or the like is provided with an earphone jack to which a plug of an earphone is connected. The earphone jack and the plug are illustrated in exemplary views of FIGS. 1 and 2.
FIG. 1 is a perspective view which illustrates a conventional earphone jack and a plug before connection, and FIG. 2 is a plan view of FIG. 1.
As shown, a plug 10 integrally connected to an earphone includes a plurality of terminals 12, 13 and 14 which are electrically separated from one another by insulating portions 11 that are formed at a certain interval along a direction in which the plug 10 fits into the earphone jack 20. The illustrated plug 10 is a three pole plug, and the terminals 12, 13 and 14 may be a mike terminal, a speaker terminal and a ground terminal, respectively. Also, the terminals 12, 13 and 14 may be a first speaker terminal, a second speaker terminal and a ground terminal, respectively.
An earphone jack 20 into which the plug 10 fits includes a housing 21 formed as a rough rectangular parallelepiped shape and having at its center an insertion hole 22 into which the plug 10 can be inserted, and a plurality of contact terminals 23, wherein one side of each contact terminal 23 is disposed inside the insertion hole 22 to contact with each terminal 12, 13 and 14 of the plug and the other side thereof is exposed to the outside to be connected with a circuit component. The housing is commonly formed of a synthetic resin material.
The conventional earphone jack constructed in the aforementioned manner has the following problem.
First, a plug applied to a mobile terminal has a standardized diameter of 2.3±0.1 mm, and the insertion hole of the earphone jack is formed corresponding to the plug. Accordingly, if an outer diameter of the plug is 2.4 mm and an inner diameter of the insertion hole is 2.2 mm, namely, if the outer diameter of the plug is greater than the inner diameter of the insertion hole, the insertion itself cannot be made smoothly. Also, if the inner diameter of the insertion hole is greater than the outer diameter of the plug, the insertion is made smoothly but the contact between the terminals becomes loose, which may create noises or cause the earphone to be separated from the earphone jack all of a sudden.
Also, a special locking device may be additionally provided to prevent the sudden separation of the plug from the earphone jack. However, in this case, additional installation of the special locking device is not easy because of limited room within the housing and, manufacturing costs are increased and manufacturing processes become complicated.